Bodily cancers are commonly treated using radiation therapy. Radiation therapy employs high energy radiation to kill cancer cells. One type of radiation therapy is brachytherapy, in which a source of radiation is in direct contact with an afflicted tissue. A common brachytherapy treatment, transperineal seed implantation, involves placing radioactive seeds in the prostate gland to kill prostate gland cancer cells. A physician employs tools such as ultrasound, computerized tomography (“CT”) scans, and X-ray images in concert with dose-planning computer software programs to evaluate the medical condition of a patient. The physician constructs an optimal treatment plan to evenly distribute radiation throughout the afflicted tissue. Radioactive seeds of discrete radioactive strengths are inserted through multiple implantation needles at positions in the prostate gland corresponding to the treatment plan. Multiple implantation needles are required to insert the radioactive seeds into multiple locations in the afflicted tissue, with each needle containing a specified arrangement of the radioactive seeds.
Although brachytherapy is perhaps most often effected by needle implantation, other implantation methods have also been used. One example is a configuration employing seeds and sutures. To make such a configuration, the physicians have utilized a seed product (e.g., Seed in Carrier, manufactured by Oncura) that consists of seeds disposed within a suture material. The sutures are weaved through a piece of bioabsorbable fabric to yield a planar array of seeds. This array is then used to irradiate a tumor bed, most commonly following a lung resection, by sewing the array to the wall of the tumor bed.
Gross surgical removal of tumorous tissue can leave behind traces of cancerous tissue which can result in mestatasis or recurrence of the tumor. Thus, the site of removal of a tumor is often treated postoperatively in an attempt to destroy any such diseased tissue left behind by the surgery. Conventional techniques for treating the site of surgical removal of a tumor include post-operative administration of radiation, chemotherapy, and/or heat. Another method is disclosed in U.S. Pat. No. 5,030,195, the disclosure of which is incorporated by reference herein. In accordance with that disclosure, seeds can be threaded into a mesh, and the mesh embedded in a nonabsorbable silicone compound. Once the exact location and extent of a tumor is determined, the tumor is removed, and the mesh/silicone material is embedded in a region where residual tumor cells may exist.
Proper seed placement and seed retention at the implantation site strongly influence the success or failure of a brachytherapy procedure. As described above, seed implantation devices may contain a plurality of seeds that may be separated by spacers. Prior implantation devices and methods do not reliably maintain proper seed spacing during and after implantation. Therefore, a device and/or method of reliably maintaining proper seed spacing during and after implantation would be of great benefit to brachytherapy patients.
Loose seeds implanted in the prostate, especially those that are extra-capsular (located outside the capsule of the prostate), may possibly migrate within the patient. Because extra-capsular tissue is less dense than tissue within the capsule of, e.g., the prostate, prior brachytherapy seed implantation devices and methods cannot effectively maintain the location of seeds in the extra-capsular material. These seeds may migrate and fail to provide radiation where needed. Migrating radioactive seeds not only fail to provide needed radiation therapy at the treatment site, but may cause damage to other radiation-sensitive areas of the body. Therefore, a device and/or method of preventing migration of radioactive seeds in tissues and/or fluids of varying densities and consistencies would be of great benefit to brachytherapy patients.
In view of the above, it would be desirable to have an implant, whether standard or custom, that is capable of delivering radiation to a patent in need thereof without the above-mentioned disadvantages.